In recent years, a radiation image pickup unit that acquires an image based on radiations such as X-rays, as an electric signal has been developed (for example, PTL 1). Such a radiation image pickup unit is roughly classified into so-called indirect conversion type and direct conversion type. In the indirect conversion type radiation image pickup unit, for example, a wavelength conversion substrate (a scintillator plate) including a conversion layer that converts X-rays into visible light and a sensor substrate including a photoelectric conversion element that generates an electric signal based on visible light may be bonded to each other.